I would say they are very similar in performance. So the determining factor would be who's the better driver behind the wheel

 

ultimately thats what it comes down to.

 

If you want to talk about what's fastest on track, all-stock, there's very little difference between any manual transmission RX-8s. The Shinka and 40AE have Bilstein shocks, the R3 has more aggressively tuned Bilstein shocks. The R3 has a slightly stiffer rear swaybar, although the swaybar doesn't seem like it would contribute significantly to the roll stiffness anyway. There's about a 5% gearing difference between the S1 and S2, for 5% more torque in each gear but having to shift at a 5% lower speed. All that is pretty minor. Cars with sunroofs and electric seats are going to be quite a bit heavier, which probably matters more on track than the other stuff.

Once you start modifying the cars, even if it's just for "Stock" autocross where you can change the shocks and wheels, most of those differences disappear except for the weight.

But none of that seems relevant to what the original poster was interested in, which had to do with the stock appearance of his GT. In answer to him, the R3 Bilsteins won't change the appearance, and the R3 wheels list for $5000/set new at a Mazda dealer.

 

That confirms what I was describing above. Test driving these cars back to back they all fell very similar.

 

yep, according to forza4 (iknow iknow, but i cant find any other data...)

The 2011 R3 weighs in at: 3065lbs
The 2004 Mazdaspeed rx8 GT (all mazdaspeed goodies with GT seats, presumably power seats, sunroof) weighs in at: 3100lbs

The difference isnt that much at all.

anyway, we still dont know if the OP owns a 2010 GT or is looking to buy a 2010 GT that he saw. Just trying to give other options.

 

Guess you missed my comment.

 

I just bought the last new R3 wheel in the country. It was $1000.

 

If I'm not mistaken that post you quoted was from 8 years ago. Poster may very well be dead by now.